The utility model relates to a safety device for an elevator shaft during the constructing process of houses. The safety device comprises a reinforced net with the dimension matched with that of the elevator shaft and a protective cover board covered with a cover. The reinforced net comprises a plurality of transversal and longitudinal reinforcing steel bars which are welded at a certain interval; the transversal and longitudinal reinforcing steel bars extend a certain dimension from the outer edge of the rectangular reinforced net; and the protective cover board is connected with the reinforced net in a binding manner at four corners. Compared with the prior art, the reinforced net is anchored into the circumjacent beam of a floor slab with a major structure or the reinforcing steel bars of the floor slab by using a relatively permanent device; the method for covering the cover on the protective board replaces the prior art, so that the falling accidents from the elevator shaft which is likely to occur are eliminated. Meanwhile, the utility model can save a large amount of lease cost of steel tubes and fasteners and the purchasing and the installation cost of bamboo rails and elevator guard gates, as well as a large amount of labor costs, and has simple construction. The utility model has good economic and social benefits.